US20240134212A1 - Ophthalmic lens having morphed sinusoidal phase shift structures - Google Patents

Abstract

An ophthalmic lens includes an optic comprising an anterior surface, a posterior surface, and an optical axis. At least one of the anterior surface and the posterior surface has a surface profile including a base curvature and a plurality of morphed sinusoidal phase shift structures. The base curvature may correspond to a base optical power of the ophthalmic lens, and the morphed sinusoidal phase shift structures may be configured to extend depth of focus of the ophthalmic lens at intermediate or near viewing distances.

Description

PRIORITY CLAIM
• This application is a continuation of U.S. Non-Provisional application Ser. No. 16/950,456 filed Nov. 17, 2020, which is a continuation of U.S. Non-Provisional application Ser. No. 16/043,457 filed Jul. 24, 2018 and now issued as U.S. Pat. No. 10,871,659, and claims the benefit of priority of U.S. Provisional Patent Application Ser. No. 62/536,044 titled “OPHTHALMIC LENS HAVING MORPHED SINUSOIDAL PHASE SHIFT STRUCTURES,” filed on Jul. 24, 2017, whose inventors are Xin Hong, William Andrew Maxwell and Xin Wei, all of which are hereby incorporated by reference in its entirety as though fully and completely set forth herein.
FIELD
• This present disclosure relates generally ophthalmic lenses and, more particularly, to ophthalmic lenses having extended depth of focus to increase pseudo-accommodation for intermediate and near vision.
BACKGROUND
• Cataract surgery is one of the most common ophthalmic surgeries and involves the replacement of the cataractous crystalline lens with an artificial intraocular lens (IOL). Typically, a monofocal intraocular lens (with a fixed focal length) is placed in the capsular bag to provide the best distance vision. While patients implanted with monofocal IOLs have good distance vision, quality of vision at intermediate and near is often insufficient to support activities of daily living. Specifically, a good continuous range of vision at near has become increasingly significant to patients because of daily tasks related to computers, mobile devices and other technologic advances. Accordingly, there is a need for an IOL, as well as contact lenses, to provide an extended and continuous range of functional vision at intermediate/near viewing distances.
SUMMARY
• The present disclosure generally concerns multifocal ophthalmic lenses (e.g., IOLs, rigid and soft contact lenses, etc.) that provide both satisfactory distance vision and that extend the depth-of-focus at a range of intermediate to near viewing distances. In certain embodiments, an ophthalmic lens includes an optic comprising an anterior surface, a posterior surface, and an optical axis . At least one of the anterior surface and the posterior surface comprise a surface profile including a base curvature and a morphed sinusoidal phase shift (MSPS) structure. The base curvature may correspond to a base optical power of the ophthalmic lens, and the morphed sinusoidal phase shift structure may be configured to extend depth of focus of the ophthalmic lens at intermediate or near viewing distances and may comprise morphed sinusoidal phase shift zones.
• In certain variants, the morphed sinusoidal phase shift structures are configured to extend depth of focus at intermediate or near viewing distances in the range of 30-55 cm or 33-50 cm.
• The surface profile of the lens may be defined as:
• 
  Z_optic=Z_base+Z_MSPS
• wherein Z_basedefines the surface profile of the base curvature and Z_MSPSdefines the plurality of morphed sinusoidal phase shift structures. Further, Z_basemay be defined as
• $Z_{base}\left(r\right)=\frac{c{\mathrm{<figure-callout\; label="r"\; filenames="US20240134212A1-20240425-D00003.png,US20240134212A1-20240425-D00004.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}{1+\sqrt{1-\left(1+k\right){\mathrm{<figure-callout\; label="c"\; filenames="US20240134212A1-20240425-D00003.png,US20240134212A1-20240425-D00004.png"\; state="\{\{state\}\}">c</figure-callout>}}^2{\mathrm{<figure-callout\; label="r"\; filenames="US20240134212A1-20240425-D00003.png,US20240134212A1-20240425-D00004.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}}+a_2{\mathrm{<figure-callout\; label="r"\; filenames="US20240134212A1-20240425-D00003.png,US20240134212A1-20240425-D00004.png"\; state="\{\{state\}\}">r</figure-callout>}}^2+a_4{r}^4+a_6{r}^6+a_8{r}^8+a_{10}{r}^{10}\dots +a_n{r}^n$
• where r denotes a radial distance from the optical axis, c denotes a base curvature of the surface, k denotes a conic constant, and a₂, a₄, and a₆are, respectively, second, fourth, and sixth order coefficients.
• Additionally, Z_MPSSmay be defined as:
• $\begin{array}{cc}{Z}_{MSPS}\left(r\right)=M_i\frac{T_i^P}{\pi }\left(1-\cos \left(\frac{r-R_i}{T_i^P}\pi \right)\right),& R_i\le r<R_i+T_i^P\end{array}$$\begin{array}{cc}{Z}_{MSPS}\left(r\right)=M_i\frac{T_i^P}{\pi }\left(1-\cos \left(\frac{r-R_i-T_i^P}{R_{i+1}-R_i-T_i^P}\pi +\pi \right)\right),& R_i+T_i^P\le r<R_{i+1}\end{array}$
• where r denotes a radial distance from the optical axis, R_iand R_i+1are the starting and ending radial positions of each zone, M_iare step heights of each zone, T_i^Pare the critical points within each zone, and i indicates zone numbers.
• In certain embodiments, the present disclosure may provide one or more technical advantages. For example, embodiments of the disclosure combine a base monofocal aspheric curvature with a morphed sinusoidal phase shift structure to provide an extended range of functional vision at near and/or intermediate distances, while maintaining distance visual acuity and a safety profile similar to that of a typical monofocal lens. Using morphed sinusoidal phase shift structures may eliminate discontinuous diffractive structures and small aperture or pinhole effects found in conventional EDF designs. Accordingly, embodiments may enable patients to enjoy visual range superior to conventional EDF or monofocal designs with fewer visual disturbances, reduced loss of light, and greater efficiency.
BRIEF DESCRIPTION OF THE DRAWINGS
• For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings in which like reference numerals indicate like features and wherein:
• FIGS.1A-1B illustrate an example embodiment of an extended depth of focus IOL having morphed sinusoidal phase shift structures, according to certain embodiments;
• FIG.2 illustrates an exemplary surface sag plot of a base monofocal optic;
• FIG.3 illustrates an example of added surface sag resulting from multiple morphed sinusoidal phase shift structures on an optic;
• FIGS.4A and4B illustrate characteristics of an optic, according to certain embodiments;
• FIGS.5A and5B illustrate characteristics of an optic, according to certain embodiments; and
• FIGS.6A and6B illustrate characteristics of an optic, according to certain embodiments.
• One skilled in the art will understand that the drawings, described below, are for illustration purposes only, and not intended to limit the scope of the disclosure.
DETAILED DESCRIPTION
• The present disclosure generally concerns ophthalmic lenses (e.g., IOLs and contact lenses) that provide both satisfactory distance vision and extended depth-of-focus at ranges in intermediate to near viewing distances. More particularly, embodiments of the present disclosure provide an ophthalmic lens such as an IOL or contact lens having (1) a mono-focal aspheric lens to partially or completely correct patient's lower-order and/or higher-order aberrations at distances and (2) morphed sinusoidal phase shift (MSPS) structures added on anterior and/or posterior lens surfaces to extend the depth-of-focus at a range of intermediate-near viewing distances. Such MSPS-enhanced lens designs may provide an extended and continuous range of functional vision at intermediate/near viewing distances (e.g., from 50 cm to 33 cm) while maintaining distance visual acuity and a safety profile similar to that of a monofocal lens.
• FIGS.1A-1B illustrates an example embodiment of anIOL100 having extended depth of focus for intermediate-near vision, according to certain embodiments. IOL100 includes an optic102 having ananterior surface104 and aposterior surface106 that are disposed about anoptical axis108. Optic102 may be convex on both sides (biconvex) and made of a soft plastic that can be folded prior to insertion, allowing placement through an incision smaller than the optic diameter of the lens.IOL100 may further include a plurality ofhaptics110 generally operable to position and stabilizeIOL100 within the capsular bag of a patient's eye. Althoughhaptics110 having a particular structure are illustrated inFIG.1, the present disclosure contemplateshaptics110 having any suitable shape and structure for stabilizingIOL100 within the capsular bag, the ciliary sulcus, or any other suitable location within the eye.
• The anterior surface104 (or, in other embodiments, posterior surface106) of optic102 may have a base curvature corresponding to a base optical power of theIOL100. The base optical power ofIOL100 typically corresponds to the distance vision of the patient. However, this is not required. For example, a non-dominant eye may have an IOL with a base optical power is slightly less than the corresponding distance power for the patient to improve overall binocular vision for both eyes. In certain embodiments, the base curvature may be aspheric. It is noted that, although the figures illustrateanterior surface104 of optic102 as having a particular surface profiles, features, and characteristics, the present disclosure contemplates that profiles, features, and characteristics may additionally or alternatively be located onposterior surface106 of optic102. Further, although the disclosed examples primarily discuss an aspheric monofocal base lens, the MSPS structures described herein may be combined with other base lens profiles. Accordingly, the disclosure is not limited to aspheric monofocal optics, but includes other variants which would be contemplated by one skilled in the art.
• In addition to a base curvature, the anterior surface104 (or, in other embodiments, posterior surface106) of optic102 may include a plurality of regions. For example,anterior surface104 may include aMSPS region112, which may extend from theoptical axis108 to a first radial boundary, and arefractive region114, which may extend from the first radial boundary to a second radial boundary (e.g., the edge of the optic102). Althoughanterior surface104 ofoptic102 is depicted and described as having two regions (MSPS region112 and refractive region114), the present disclosure contemplates thatanterior surface104 orposterior surface106 ofoptic102 may include a surface profile having any suitable number of regions. As just one example,anterior surface104 could alternatively include a surface profile having two refractive regions separated by a diffractive region.
• MSPS region112 may comprise a morphed sinusoidal phase shift (MSPS)structure116 having a plurality of MSPS features118 (also known as zones). As described in detail below, theMSPS structure116 may be added to a base curvature of amonofocal aspheric optic102 to form an IOL which may provide pseudophakic patients with satisfying distance vision and continuous range of vision correction from intermediate to near distances (e.g., from 2D-3D, 1.5D-2.5D, 1.5D-3.0D).
• The surfaces of an MSPS-enhancedoptic102 may be described mathematically. In particular, optic102 may comprise a base aspheric mono-focal lens that corrects a patient's lower and/or higher aberrations at a distance and may have particular sag profile. Sag is an indication of the z-component of the displacement of the optical surface from the vertex at a radial distance r from the optical axis. The anterior and posterior surface sag profiles for the base lens (Z_base) ofoptic102 can be described according to Equation (1):
• $\begin{array}{cc}{Z}_{base}\left(r\right)=\frac{c{\mathrm{<figure-callout\; label="r"\; filenames="US20240134212A1-20240425-D00003.png,US20240134212A1-20240425-D00004.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}{1+\sqrt{1-\left(1+k\right){\mathrm{<figure-callout\; label="c"\; filenames="US20240134212A1-20240425-D00003.png,US20240134212A1-20240425-D00004.png"\; state="\{\{state\}\}">c</figure-callout>}}^2{\mathrm{<figure-callout\; label="r"\; filenames="US20240134212A1-20240425-D00003.png,US20240134212A1-20240425-D00004.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}}+a_2{\mathrm{<figure-callout\; label="r"\; filenames="US20240134212A1-20240425-D00003.png,US20240134212A1-20240425-D00004.png"\; state="\{\{state\}\}">r</figure-callout>}}^2+a_4{r}^4+a_6{r}^6+a_8{r}^8+a_{10}{\mathrm{<figure-callout\; label="r"\; filenames="US20240134212A1-20240425-D00003.png,US20240134212A1-20240425-D00004.png"\; state="\{\{state\}\}">r</figure-callout>}}^{10}+\dots +a_n{r}^n& \mathrm{Eq}.\left(1\right)\end{array}$
• • Wherein,
  • r denotes a radial distance from the optical axis;
  • c denotes a base curvature of the surface;
  • k denotes a conic constant;
  • a₂is a second order deformation constant;
  • a₄is a fourth order deformation constant;
  • a₆is a sixth order deformation constant.
  • a₈is a eighth order deformation constant; and
  • a₁₀is a tenth order deformation constant.
• FIG.2 is a surface sag plot based on Equation (1). The curvature of anterior and posterior surfaces may be optimized such that the base lens corrects defocus of the patient's eye. Moreover, the conic constant (k) and higher-order coefficients (e.g., a₂, a₄, a₆, a₈. . . ) can be adjusted to yield different levels of spherical aberration for the design ofoptic102. Such spherical aberration, when combined with the corneal spherical aberration of an individual patient or an average patient population, can provide patients with optimal distance vision correction.
• To extend depth of focus of the base lens at intermediate-near distances, aMSPS structure116 comprising as plurality ofMSPS zones116 may be added to eitheranterior surface104 orposterior surface106 ofoptic102. The anterior or posterior surface sag profiles added by the MSPS structure (Z_add) can be described according to Equation (2):
• $\begin{array}{cc}\begin{array}{cc}{Z}_{MSPS}\left(r\right)=M_i\frac{T_i^P}{\pi }\left(1-\cos \left(\frac{r-R_i}{T_i^P}\pi \right)\right),& R_i\le r<R_i+T_i^P\end{array}& \mathrm{Eq}.\left(2\right)\end{array}$$\begin{array}{cc}{Z}_{MSPS}\left(r\right)=M_i\frac{T_i^P}{\pi }\left(1-\cos \left(\frac{r-R_i-T_i^P}{R_{i+1}-R_i-T_i^P}\pi +\pi \right)\right),& R_i+T_i^P\le r<R_{i+1}\end{array}$
• • Wherein,
  • r denotes a radial distance from the optical axis;
  • R_iand R_i+1are the starting and ending radial positions of each zone;
  • M_iare step heights of each zone;
  • T_i^Pare the critical points within each zone;
  • i indicates zone numbers i=0, 1, 2, 3 . . . .
• FIG.3 plots an example of added surface sag based on Equation (2). As can be seen in the curve on the left side ofFIG.3, a first sinusoidal phase shift zone310 (i=0) spans from R₀to R₁. M₀is the step height ofzone310 and T₀^Pis the critical point corresponding to the radial distance of the peak of zone310 (at point M₀) from R₀. A second sinusoidal phase shift zone320 (i=1) spans from R₁to R₂. M₁is the step height ofzone320 and T₁^Pis the critical point corresponding to the radial distance of the peak of zone320 (at point M₁) from R₁. This pattern continues in an analogous manner for additional zones.
• The total sag of optic102 (Z_optic) is a combination of base surface sag Z_basewith morphed sinusoidalphase shift structure116 described by Z_MPSSand may be described according to Equation (3) below:
• 
  Z_optic=Z_base+Z_MSPS  Eq. (3)
• Accordingly, a variety of improved optical designs may be developed by adding a MSPS structure to an aspheric monofocal base lens. In one example, morphedMSPS116 comprises seven MSPS zones (i=0-6) as shown in Table 1, below:

• TABLE 1
  Zone No. (i)	0	1	2	3	4	5	6
  Ri+1 − Ri(mm)	0.56	0.39	0.35	0.46	0.39	0.49	0.45
  TiP/(Ri+1− Ri)	0.56	0.79	0.87	0.56	0.75	0.64	0.82
  Mi(μm)	0.20	0.31	0.16	0.12	0.12	0.24	0.33

• An optic102 which includes aMSPS structure116 in accordance with the parameters of Table 1 may provide extended depth of focus between 2D and 3D. Optical path delay (opd, as a function of radial distance in millimeters) and through-focus modular transfer function (MTF, as a function of target vergence (TV(D)) curves for a 3.4 mm entrance pupil (EP) and the parameters of Table 1 are plotted inFIGS.4A and4B.
• In another example,MSPS structure116 comprises seven MSPS zones (i=0-6) as shown in Table 2, below:

• TABLE 2
  Zone No. (i)	0	1	2	3	4	5	6
  Ri+1 − Ri(mm)	0.43	0.40	0.41	0.27	0.48	0.56	0.59
  TiP/(Ri+1− Ri)	0.81	0.64	0.51	0.66	0.90	0.64	0.63
  Mi(μm)	0.25	0.15	0.14	0.28	0.25	0.22	0.29

• An optic102 which includes aMSPS structure116 in accordance with the parameters of Table 2 may provide extended depth of focus between 2D and 3D. Optical path delay (opd) and through-focus modular transfer function (MTF) curves for a 3.4 mm entrance pupil (EP) and the parameters of Table 2 are plotted inFIGS.5A and5B.
• In another example,MSPS structure116 comprises seven MSPS zones (i=0-6) as shown in Table 3,below:

• TABLE 3
  	Zone No. (i)	0	1	2	3	4	5	6
  	Ri+1 − Ri(mm)	0.56597	0.56263	0.55974	0.5578	0.35399	0.47423	0.59278
  	TiP/(Ri+1− Ri)	0.53174	0.89869	0.72774	0.70043	0.66239	0.80014	0.50225
  	Mi(μm)	0.14009	0.31403	0.12667	0.13384	0.35788	0.16124	0.39076

• An optic102 which includes aMSPS structure116 in accordance with the parameters of Table 3 may provide extended depth of focus between 1.5D and 2.5D. Optical path delay (opd) and through-focus modular transfer function (MTF) curves for a 3.4 mm entrance pupil (EP) and the parameters of Table 2 are plotted inFIGS.6A and6B.
• Accordingly, embodiments of the disclosure combine a base monofocal aspheric curvature with a MSPS structure to provide an extended range of functional vision at near and/or intermediate distances, while maintaining distance visual acuity and a safety profile similar to that of a typical monofocal IOL. Certain variants provide extended and continuous range of functional vision at near distances between 33 cm and 50 cm while maintaining distance visual acuity.
• Combining a base aspherical monofocal lens with a MSPS structure as described herein may provide numerous advantages and benefits. For example, the image quality of the base lens at distance may begin dropping off in a well-controlled manner to an extent where the distance vision (e.g. visual acuity or contrast sensitivity) is still satisfying to patients. Moreover, as the image quality at distance drops off, the image quality at a range of intermediate/near defocus positions (e.g. 2-3D or 1.5-2.5D) may begin to increase, enabling patients to resolve targets at much wider focus range at intermediate/near distances.
• Accordingly, while previous extended depth of focus (EDF) designs typically extend depth of focus from distance to intermediate distances, MSPS-enhanced designs described herein are capable of extending depth of focus around intermediate and near viewing distances (e.g., from 2D to 3D). And compared with previous monofocal designs where vision is corrected at two distinct points (near and far), MSPS-enhanced designs described herein extend depth of focus around intermediate or near viewing distances continuously (e.g., from 2D to 3D). As a result, the present disclosure addresses patient needs and benefits that are not addressed by prior EDF or monofocal lens designs.
• Moreover, the MSPS technology described herein does not rely on discontinuous diffractive structures used in conventional EDF IOL designs. By eliminating discontinuous diffractive structures (which typically induce visual disturbances), disclosed lens designs may provide improved optical performance compared with conventional diffractive lenses. Similarly, the presently-described MSPS technology does not require small aperture or pinhole effects to extend depth of focus. Hence, the improved MSPS-enhanced lens designs contemplated herein can further improve optical performance by avoiding loss of light and improving efficiency relative to such existing designs. In addition, extra spherical aberration can be added on either the anterior or posterior surfaces of improved lenses disclosed herein to achieve optical distance vision at various pupil sizes, providing additional flexibility for customization of MSPS-enhanced lenses.
• It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. For example, although the above-described embodiments relate to ophthalmic lens is an IOL, one skilled in the art will appreciate that the MSPS features and techniques described herein are also applicable to soft or rigid contact lenses. It will also be appreciated that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which alternatives, variations and improvements are also intended to be encompassed by the following claims.

Claims (7)

1. An ophthalmic lens, comprising:

an anterior surface, a posterior surface, and an optical axis, at least one of the anterior surface and the posterior surface having a surface profile comprising a morphed sinusoidal phase shift structure;

wherein the morphed sinusoidal phase shift structure is in the form of an asymmetric sinusoidal wave and comprises a plurality of zones, each zone comprising a single sinusoidal period.

2. The ophthalmic lens ofclaim 1, wherein the morphed sinusoidal phase shift structure is configured to provide an extended depth of focus of the ophthalmic lens to provide intermediate or near viewing distances in the range of 30-55 cm.

3. The ophthalmic lens ofclaim 1, wherein the morphed sinusoidal phase shift structure is configured to provide an extended depth of focus of the ophthalmic lens to provide intermediate or near viewing distances in the range of 33-50 cm.

4. The ophthalmic lens ofclaim 1, wherein each of the plurality of zones further comprises a step height different from a step height of an adjacent zone.

5. The ophthalmic lens ofclaim 1, wherein the morphed sinusoidal phase shift structure comprises at least seven zones.

6. The ophthalmic lens ofclaim 1, wherein the ophthalmic lens comprises an intraocular lens.

7. The ophthalmic lens ofclaim 1, wherein the ophthalmic lens comprises a contact lens.

Images